Yes John, thanks for the link unfortunately it looks like Adobe hasn't fixed the problem yet. Shame they didn't do more testing before they released it. Would have saved them a lot of embarrassment and us a lot of frustration.
No, it really has made a difference for most. I am using it and while there are still some issues (2nd monitor lag, etc) performance is very good. Mind you I haven't had the issues others have, no rhyme, no reason!!
Well LR4.1RC2 does seem to work better but still slow in develop especially when working at 100% doesn't move smoothly when navigating around image, but much better than LR4 it hasn't crashed yet either